58cc engine at sea level, ~60% humidity:
Test with MTW test reso pipe: rpm, header length cm, header dia mm; remarks
Mej 22x10, TDreso;7700;25;28; slight hunting (unstable top rpm 7600 - 7800)
Mej 24x10;TDreso;6500;25;28; slight hunting
Mej24x10;TDreso;6800;40;28; slight hunting
No hunting at richer carb settings

Tests with KS 50 reso pipe:
mej 22x10, KS50reso; 7600; 25;28; steady rpm

Tests with final (available) 4-chamber MTW tuned pipe as soon as I can manage.